karel akerman

Cayenne was starting after 2-3 tries at each start, even after I have made a 3 hour trip. Once it starts everything is just fine, though engine fault light is constantly on.
This morning it wouldn't start even no matter how many times I tried.
Battery?
1. I attached a BMW X5 diesel to start but no avail.
2. I have put in a brand new battery. Still would not start.

Basically, it cranks for several seconds then it aborts.

Crankshaft position sensor?
1. I removed the CPS underneath the car. I noticed there was a lot of steel dust accumulated on the sensor. Removed the steel dust and cleaned thoroughly.

But still the same.

Immobilizer?
My friend says the ECU doesn't allow engine to start. He thinks it's a problem with the immobilizer.
1. My car was starting until this morning with both keys although with difficulty. I tried both keys. No success.

Anybody else who had similar problem? Please help, what can I do?

nk215

Did you pull the code? You said the engine light is on so checking the code would be the first step.

When it doesn't start, does it even crank?

karel akerman

- Yes it cranks for several seconds then it aborts.

- The code I have is P0344 camshaft sensor fault. It was there for a few weeks. Despite the fault code, I was able to start until now.

nk215

I would replace both camshaft sensors as the first step. Camshaft sensor error could be from a much larger issue such as the timing chain tensioner being on the way out etc.

karel akerman

Thank you. But would the timing chain cause such an issue, like not starting at all?
When it starts engine was running with full performance, without any noise or anything. It's as if something (a missing signal) is blocking the engine.

Petza914

Does the tach needle bounce as the engine is cranking? Might be a failed crankshaft position sensor. If it doesn't know where the engine is in its rotation it won't fire the spark or injectors. On a cold start it usually ignores the camshafts for the first 2 minutes or so as it runs in open loop, then it switches to closed loop and looks for info from them. With the code you have, definitely do the camshaft sensors too.

karel akerman

thank you. Just checked, no needles are moving.
just hearing the crank, then it aborts. Battery is full.

karel akerman

thank you. Just checked, no needles are moving.
just hearing the crank, then it aborts. Battery is full.
warnings

karel akerman

Petza914

If no tach needle movement, you need a new crankshaft position sensor.

karel akerman

Thank you. Measured the crankshaft sensor it reads the correct resistance, but not sure if it still works.
The errors indicate Camshaft sensor fault. So I will definitely replace the camshaft sensors.

Jfrahm

Hmm, both sensors failing would be weird unless you have been ignoring a CEL for a while. Suspect instead a wiring harness problem, corrosion.

karel akerman

I just got the car, so I would not know what happened before.
When I got the car I ran a diagnostic and the only problem OBD saw was the camshaft 1 sensor fault. Previous owner told me it was starting on the second crank.
After this I have driven about 200 miles, then the car stopped completely. This time OBD was showing Camshaft 1 and 2 faults together.
Maybe only one sensor was enough to enable the starting circuit.

Yes it is curious that both fail one after the other.

• Could this be corrosion or connector?
  The car looks pretty clean in terms of rust. Connectors look shiny.
• Could this be an electrical issue?
  Second sensor failed after I replaced the battery. Plausible. I will measure the pins of the connectors.

Another idea about the cause:
These sensors work with hall effect so the steel particles from the chaffed off from moving parts may accumulate on the sensor, rendering them completely unusable. Although there was no failure I was checking the crankshaft sensor just-in-case. I saw that there were lots of particles attracted to the sensor head.
I have seen some guides, recommending to change these sensors at 90K. Some say that even after cleaning the steel particles sensors loose their sensitivity in time and fail. This might be the reason.

Jfrahm

The code is for an electrical fault, so unlikely to be a loss of magnetism (which is IMO unheard of for a sensor like this).
The sensor itself does not appear to have a pigtail so loss of connection actually in the sensor seems unlikely. Maybe damage to the harness connector or near to it due to strain, maybe the engine mounts are bad and causing wire chafing and bending.
There are threads on the related codes and none of the 3 I looked at indicated that replacing the sensors addressed the problem.

If it were my problem I would look at OBD2 live data from the sensors first then ohms, AC voltage, Hz and duty cycle with a DMM before taking off the intake manifold. The lack of tach twitch is a concern.

Given you had a larger problem after replacing the battery a dude might put a jumper cable from the battery negative to the engine to improve the engine ground and likewise to the frame.
-Joel.

karel akerman

I have changed the camshaft sensors but the car did not start and I still have the same problems. So I needed to go to the basics. I removed the valve covers to see what's going on inside.

Basically;

- Starter turns
- Timing chain does not turn.
- Driver side camshaft turns
- Passenger side camshaft does not turn!

So camshaft sensor was reporting correctly that there was no signal. The cause was not a bad sensor, there was no movement on the camshaft.
Attached is a video of the issue.

Hope all this helps others having similar issues.

Now it seems like a mechanical issue on the bank1 system.

Chain seems to be ok.

Any ideas on how to proceed further?